Developments to watch: Mobile microrobots

Future robots much smaller than Lincoln’s smile on a penny may locate cancer cells, enter, and deliver anti-cancer agents, or self-assemble into a structure, providing science-fiction-like advances in medicine, manufacturing, and other industries. At present, power and control remain two significant challenges, according to Dr. Igor Paprotny, assistant professor, University of Illinois at Chicago, speaking at Sensors Expo on June 25.

Mark T. Hoske

07/02/2014

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Untethered mobile microscale robotic system research began in the 1980s and continues with a growing number of researchers involved, according to Dr. Igor Paprotny, assistant professor, University of Illinois at Chicago, speaking at Sensors Expo on June 25. Progress is slow as power and control remain significant hurdles, but the prospect of micro electrical mechanical systems (MEMS) microrobots has significant potential in manufacturing, biomedicine, and surveillance. And navigation is improving, he suggested.

Paprotny, discussing current trends and future directions in microrobots, also reviewed the progress of his team, showing images and an amusing video of moving microrobots set to the "Blue Danube" waltz, including a "docking" procedure where two link.

Microrobots, by definition, operate within a 1 mm cube. Autonomous flight is proven in the insect world within that size range, he noted, showing an image of a flying butterfly parasite about 130 microns in size that appeared as a speck on the head of a butterfly.

Motive force from substrate

Paprotny's team's "MicroStressBots" use a powered substrate for motion; they're rectangular (160 x 60 microns) with a leg with a circle on the end adding 100 microns to one corner for 260 microns total. Movements are similar to those of an inchworm-scratch-drive propulsion, he called it. Dragging the arm can create a turn.

Challenges include:

Fabrication integration of a complete system at a micro scale.

Power; at present, off-board electrostatic power delivery is used.

Control; off-board control is used; it's a massively under-actuated system. At present, the robots only turn one way, although they can be made to turn with a tighter radius.

In a separate effort, a small flying robot also is under development. The microflyers, which appear like a small fan blade, 1.5 micron thick with a 300-micron wingspan, actually have a small jumping action traveling 126 microns. They use the same motive principle as a spinner solar radiometer. Paprotny acknowledged that eight students also working on this research.

Differing motive approaches are being used by other researchers, including magnetic forces (most common), biological (modified bacteria or sperm), or catalytic (with rolled-up tubules).